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Chandra and XMM-Newton Observations of the Nucleus of Centaurus A

D. A. Evans·R. P. Kraft·D. M. Worrall·M. J. Hardcastle·C. Jones·W. R. Forman·S. S. Murray
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Abstract

We present X-ray spectra of the nucleus of the nearby radio galaxy Centaurus A from observations with the XMM-Newton EPIC CCD cameras (two exposures separated by 12 months) and the Chandra HETGS. For the first time in an FRI type galaxy, we resolve fluorescent K$α$ emission from cold, neutral, or near-neutral iron at 6.4 keV, with an rms line width of $\sim$20 eV. The Fe line parameters observed are consistent with fluorescent emission from material at a large distance from the AGN, either in the form of an absorber that nearly completely surrounds the central engine or a torus that lies predominantly out of the line of sight. Unresolved emission lines from neutral Si K$α$ at 1.74 keV and neutral S K$α$ at 2.30 keV are also detected. We find no evidence in the data for a previously reported 6.8 keV broadened Fe line. The continuum spectrum is well fitted with a combination of a heavily absorbed power-law component that we relate, using Bondi theory, to accretion phenomena in the form of a standard, geometrically thin, optically thick disk, and a second, less absorbed, power-law component that we associate with emission from the subparsec VLBI radio jet.

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D. A. Evans, R. P. Kraft, D. M. Worrall, M. J. Hardcastle, C. Jones, W. R. Forman, S. S. Murray. 2004-09-22. Chandra and XMM-Newton Observations of the Nucleus of Centaurus A. https://doi.org/10.1086/422806

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